A Guide To The Esophageal pH Monitoring Test 

(Catheter Based)
Please contact us:
– to cancel or reschedule your procedure 
– for pre-procedure prep or medication questions  

What is the purpose of an Esophageal pH monitoring test?

Esophageal pH monitoring is a test used to evaluate for gastroesophageal reflux disease and to determine the effectiveness of medications that prevent acid reflux.   

This test measures the amount of acid refluxing or backing up from the stomach into the esophagus (food pipe). Esophageal pH monitoring is used in several situations to assess for gastroesophageal reflux disease (GERD).
The first is to evaluate typical symptoms of GERD such as heartburn and regurgitation that do not respond to treatment with medications. In this situation, there may be a question as to whether the patient has gastroesophageal reflux disease or if anti-acid medications are adequate to suppress acid production. 

  The second is when there are atypical symptoms of GERD such as chest pain, coughing, wheezing, hoarseness and sore throat. In this situation, it is not clear if the symptoms are due to gastroesophageal reflux. 
Occasionally, this test can be used to monitor the effectiveness of medications used to treat GERD. The test is often used as part of a pre-operative evaluation before anti-reflux surgery.  

Preparation for the test

  • If you are on blood thinners, it is important to inform us before scheduling your procedure so we can check with your doctor whether you will be able to stop taking these medications before your procedure.
  • Do not eat or drink after midnight the night before the test.
  • If you are diabetic, you might need to talk to your doctor about how to manage your medications while fasting.
  • Stop all medications used to treat acid reflux or that are known to interfere with gastric function, unless your doctor has told you to stay on your medications, as in rare cases your physician may want you to continue these medications up to and during the test to determine how effective they are in suppressing acid production.

If advised to stop medications then:
  • Stop 1 week prior to testing: Prilosec (omeprazole), Prevacid (lansoprazole), Nexium (esomeprazole), Aciphex (rabeprazole), Protonix (pantoprazole), Dexilant (dexlansoprazole)
  • Stop 72 hours prior to testing: Zantac (ranitidine), Pepcid (famotidine), Axid (nizatidine), Tagamet (cimetidine)
  • Stop 24 hours prior to testing: Maalox, Mylanta, Tums, Rolaids, Amphogel, Gaviscon
  • Please note that your procedure may be canceled if you do not follow the instructions carefully.
If you have questions about other medications, then please talk with your physician. 



In order to determine the correct placement of the esophageal pH probe, it may be necessary to perform a short test called Esophageal Manometry (see additional instructions). 

-The nose is numbed for a short time. A thin wire-sized plastic catheter is passed into one nostril, down the back of the throat and into the esophagus as the patient swallows.

-The tip of the catheter contains a sensor that senses acid. The sensor is positioned in the esophagus so that it is just above the lower esophageal sphincter, a specialized area of esophageal muscle that lies at the junction of the esophagus and stomach which prevents acid from refluxing back up into the esophagus. Sometimes the probe has other pH sensors to measure pH in the stomach and the upper esophagus.

-These extra sensors do not change the size of the small catheter. Placing the probe takes approximately 10 minutes. No sedation is necessary. The other end of the small catheter comes out of the nose and is connected to a small battery-powered recorder that is worn on a strap over the shoulder. The patient is sent home with the catheter and recorder in place. During the 24 hours that the catheter is in place, the patient goes about his/her usual activities. Meals, periods of sleep and symptoms are recorded by the patient in a diary and by pushing buttons on the recorder. The diary helps the doctor to interpret the results. The patient returns the next morning for the removal of the catheter. Once the catheter has been removed, the recorder is attached to a computer, where the data recorded can be downloaded and analyzed. 

-There are very few side effects of esophageal pH monitoring. There may be mild discomfort in the back of the throat while the catheter is in place. The vast majority of patients have no difficulty eating, sleeping, or going about their daily activities. Most patients, however, prefer not to go to work because they feel self-conscious about the catheter protruding from their noses.   
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